C++ program to the Power of a number
Power of a number in C++
In this post we will see various methods to calculate Power of a Number in C++.
We need the following to calculate power of number - Base : 5 Exponent : 3 Power = 53 = 125
Methods
- Method 1: Using Pow(base, exp) method in math.h library
- Method 2: Using Iterative Loop.
- Method 3: Enhanced iterative loop to handle negative exponent too.
- Method 4: Recursive approach
Method 1 (with inbuilt function)
This method handles all cases, when exponent/bases are integers/decimals or positive/negative
Code
// This method handles all cases,
// when exponent/bases are integers/decimals or positive/negative
// pow function is contained in math.h library
#include<iostream>
#include<math.h>
using namespace std;
int main()
{
double base = 1.5;
double expo1 = 2.5;
double expo2 = -2.5;
double res1, res2;
// calculates the power
res1 = pow(base, expo1);
res2 = pow(base, expo2);
cout << base << " ^ " << expo1 << " = " << res1 << endl;
cout << base << " ^ " << expo2 << " = " << res2 << endl;
return 0;
}Output
1.5 ^ 2.5 = 2.75568
1.5 ^ -2.5 = 0.362887
Method 2 (without inbuilt function)
Sometimes, the interviewer may ask to calculate power without using the inbuilt function. We can do so in the following way but it has some trade-offs.
Only works when –
- When exponent is positive
- When exponent is integer
Code
Run
// Only works when exponent is positive integer
#include<iostream>
using namespace std;
int main()
{
double base = 1.5;
// Works only when exponent is positive integer
int expo = 2;
double res = 1.0;
while (expo != 0) {
res *= base;
expo--;
}
cout << "Result = " << res;
return 0;
}Output
Result = 2.25
Method 3 (without inbuilt function)
We solve the previous issue where code wasn’t able to handle negative exponent. But it still has the following issue, it doesn’t work when –
- When exponent is decimal
Code
Run
// Only works when exponent is integer
#include<iostream>
using namespace std;
int main()
{
double base = 1.5;
int expo = -2;
double res = 1.0;
while (expo > 0) {
res *= base;
expo--;
}
while (expo < 0) {
res /= base;
expo++;
}
cout << "Result = " << res;
return 0;
}Output
Result = 0.444444
Method 4 (Using Recursion)
This method works on recursion in C++. But it still has the following issue, it doesn’t work when –
- When exponent is decimal
Code
Run
// Only works when exponent is integer
#include<iostream>
using namespace std;
double power(double base, int exp) {
if (exp > 0)
return (power(base, exp - 1) * base);
else if (exp < 0)
return (power(base, exp + 1) / base);
else
return 1;
}
int main()
{
double base = 1.5;
int expo = -2;
double res = 1.0;
cout << "Result = " << power(base, expo);
return 0;
}Output
Result = 0.444444
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#include
using namespace std;
int main()
{
int x, y, i, pro=1;
cout<> x >> y;
for (i=1; i<=y; i++)
pro= pro* x;
cout<< "\n final value= " <<pro;
return 0;
}
https://prepinsta.com/discord/
Kindly refer this link.
//using loop
#include
using namespace std;
int main()
{
int base,power;
cin>>base>>power;
int result=1;
for(int i=1;i<=power;i++)
result=result*base;
cout<<result;
return 0;
}